1. Field of the Invention
The present invention relates to the control of emissions by devices in sensitive environments. More particularly, the present invention relates to controlling emissions by transmitting signals to devices that indicate levels of functionality of devices.
2. Related Art
There are currently a large number of devices that generate emissions having deleterious effects in the area surrounding the devices (or, the xe2x80x9cenvironmentxe2x80x9d). For example, mobile telephones, portable (or, xe2x80x9claptopxe2x80x9d) computers, radios, hand held organizers, and similar devices commonly emit audible noises that persons in the environment may find unpleasant or distracting. These types of devices also emit electromagnetic radiation that may negatively affect electronic devices in the environment.
One conventional solution to the above problem is to notify, by posted warning or by personal notification, the user of a device that the device must be deactivated while in the environment. Airline flight crews use this technique in order to minimize the electromagnetic radiation emitted by devices such as mobile telephones, portable computers, radios, etc. These devices all generate electromagnetic radiation, some in the form of radio frequency (RF) noise, that may affect an aircraft""s navigation, control, and communication systems. The airline flight crew must therefore notify the users of such devices that they must deactivate them while on the aircraft, or that they must deactivate them during certain phases of the flight, such as takeoff, climb, landing, etc.
While deactivating all devices on an aircraft eliminates emissions from the devices, the conventional solution relies on the device users"" compliance with the flight crew""s orders. This is undesirable because it may be difficult for the flight crew to determine whether all device users are actually in compliance. Also, some device users may mistakenly believe that they have complied with the orders, while their devices continue to generate emissions. For example, a mobile telephone in an inactive state may continue to transmit a signal notifying nearby base stations of its location (known as xe2x80x9cpollingxe2x80x9d), generating RF emissions in the process.
While it is possible for the flight crew to ensure compliance by all passengers, it is time-consuming for the flight crew to thoroughly instruct the passengers as to what devices must be deactivated and how they must be deactivated. In addition, the requirement for devices to be deactivated is inconvenient to the passengers.
A similar problem exists in public places such as restaurants, theaters, train cars, and similar environments, in which either audible noises or electromagnetic radiation emissions from devices are undesirable. The common solution to this problem is to post a notice requiring that certain devices not be used in the environment. For example, many restaurants post such notices forbidding the use of mobile telephones within the restaurant. This conventional solution is unsatisfactory because it relies on the users of the devices to comply with the notice, and it requires monitoring to ensure compliance.
An alternative conventional solution is to insulate the environment to electromagnetic energy. This solution renders mobile telephones, radios, etc. inoperative because they cannot receive signals from outside signal sources such as base stations, telecommunication satellites, radio transmitters, etc.
This conventional solution is effective in preventing both audible and electromagnetic emissions from mobile telephones, radios, etc. in the environment. However, preventing the use of these devices in the environment is inconvenient to users of the devices. Further, insulating the environment has no effect on devices that do not communicate with signal sources outside of the environment. In addition, insulating the environment to outside communications may prevent a desired use of a device, such as the use of a mobile telephone to place an emergency call.
There is therefore a need for an effective method of controlling emissions from devices within an environment, that does not unnecessarily inconvenience device users. There is also a need for an apparatus capable of effectively controlling emissions from devices, without unnecessary inconvenience to device users.
According to a first aspect of the present invention, the disadvantages of conventional solutions are overcome, and other advantages are achieved, by using a control device to transmit signals to one or more devices in the environment, the signals indicating a level of functionality required for the devices in the environment. The control device selects a level of functionality for each device that results in an acceptable level of emissions from each device while it is in the environment.
According to the first aspect, the control device controls the functionality of devices in an environment so that emissions from the devices are maintained at an acceptable level. In addition, depending upon the conditions within the environment, the control device can either increase or decrease the levels of functionality of devices within the environment. This aspect ensures that emission levels are maintained at an acceptable level without unnecessarily inconveniencing device users.
According to a second aspect of the present invention, a control device comprises a controller, an internal transmitting device, and an external transmitting device. The internal transmitting device receives communication signals from devices in the environment, and the communication signals are transmitted outside of the environment by the external transmitting device. The external transmitting device also receives communication signals from external signal sources, these communication signals being transmitted to a corresponding device by the internal transmitting device.
According to the second aspect, the controller maintains and controls communications between the devices in the environment and the external signal sources. The control device can also include control signals and warning signals within the communications to the devices in the environment, so that emissions from the devices are maintained at an acceptable level. A further advantage is that transmit power levels for the devices in the environment may be reduced, because the transmissions from the devices need only reach the internal transmitting device within the environment.
Other aspects and advantages of embodiments of the invention will be discussed with reference to the drawing figures and to the detailed description of preferred embodiments.